This generally relates to techniques for continuous modulation of Orthogonal Frequency Division Multiplexing (OFDM) signals.
Many recent digital wireless communication systems (wireless or cable-based systems, for example) use Orthogonal Frequency Division Multiplexing (OFDM) for environments where there is strong interference or multipath reflections.
To increase statistical multiplexing gain, many communication systems assign subsets of OFDM subcarriers to individual users, terminals or electrical devices in both the upstream and downstream directions. In this manner, the data associated with a particular user, terminal or electrical device is modulated via the associated subset of OFDM subcarriers. The resultant OFDM modulated signal is then modulated via an RF carrier signal, and the resultant signal is transmitted over a wireless link. This OFDM modulation technique is commonly called Orthogonal Frequency Division Multiple Access (OFDMA).